Overhaul SFR

External Structure

Overhaul SFRs are built with a cuboidal casing. The edges must be Reactor Casings, but the faces an also be made with Reactor Glass.

The fission controller can be placed within any face of the reactor casing.

Coolant can be piped in and out via Fission Reactor Vents.

Fuel can be piped in and out via Fission Fuel Cell Ports.

Items for Irradiator recipes can be piped in and out via Neutron Irradiator Ports.

Right click any port or vent with a multitool to switch it between Input and Output mode. In output mode, they will push their contents to adjacent pipes or inventories. (Do not extract items with a servo or something similar, as they can limit the output rate)

Neutron sources are placed within the casing. (They can be seen underneath the levers in the example).

To turn on a reactor, provide it with fuel, coolant, and provide a redstone signal to all neutron sources. In order to turn off the reactor, the design must include Neutron Shields. These can be toggled with a Fission Neutron Shield Manager. (See Neutron Shields for more info)

Coolant

Coolant is inserted via a Fission Reactor Vent

Input	Output	Heat	Output Ratio
Water	High Pressure Steam	64	4
Preheated Water	High Pressure Steam	32	4
Actual values may vary based on mod configuration.

Fuels

Fuel pellets are inserted via a Fission Fuel Cell Port. Each fuel has 4 stats:

• Efficiency: The base efficiency of the fuel.
• Base Heat: The base heat generation of the fuel.
• Criticality: The amount of neutron flux required to activate a fuel cell.
• Base Time: The time, in ticks, that one fuel pellet will last in one fuel cell.

Some fuels are also self-priming. This means they do not require a neutron source.

Internal Structure

Every fission reactor contains Fuel Cells, Moderators, and Heat Sinks. They may also contain Reflectors, Irradiators, Neutron Shields, and Conductors.

Fuel Cell	Heavy Water Moderator	Beryllium-Carbon Reflector	Neutron Irradiator	Boron-Silver Neutron Shield	Water Heat Sink	Conductor

Fuel Cells

Each fuel cell can have a different fuel. To filter a fuel cell or port, right click it with a fuel pellet. Filtered cells are accessed through filtered ports.

Fuel cells must be activated for the reactor start. They become active when they receive enough neutron flux. (when flux >= fuel criticality)

Neutron flux spreads through the reactor's core through moderator lines. It originates from cells that are primed with a netron source. To prime a cell, place a neutron source in the casing with line-of-sight to the cell you want to prime.

Line-of-sight is obstructed by cells, reflectors, and irradiators, but not by heat sinks, moderators, or conductors.

You can automatically place a neutron source in the planner by shift-clicking the cell you want to prime.

The cell in the first example does not have line-of-sight to the casing, but the cell in the second one does.

Once a cell is activated, it will transmit neutron flux through all connected moderator lines. Fuel cells will not stay active unless they have enough sustained neutron flux from other active cells.

Cells gain a heat multiplier and efficiency multiplier from all connected moderator lines. The heat multiplier is equal to the number of adjacent moderator lines.

The positional efficiency is the sum of each moderator line's efficiency (which is the average of each of its moderators' efficiencies).

The total efficiency multiplier is the positional efficiency multiplied by the fuel's efficiency.

Moderators

Moderators transmit neutron flux between Fuel Cells, Reflectors, and Irradiators.

Each moderator has a flux factor and an efficiency factor.

Moderator lines can be a maximum of 4 blocks long, or half of that when connected to a reflector.

Here is a list of moderator stats:

Moderator	Flux Factor	Efficiency Factor
Graphite Moderator	10	1.1
Beryllium Moderator	22	1.05
Heavy Water Moderator	36	1
Actual values may vary based on mod configuration

The total flux of a moderator line is the sum of each moderator's flux factor. The total efficiency is the average of each moderator's efficiency factor.

In this example, the moderator line has a flux factor of 92 (10+36+10+36) and an efficiency of 105% ((1.1+1.0+1.1+1.0)/4)

The ends of moderator lines can also support heat sinks, but only if they end at a cell

For example, the beryllium moderators below can support coolers, but the graphite moderators cannot.

Reflectors

Reflectors will reflect neutron flux back to cells through moderator lines. Each reflector has a Reflectivity and Efficiency factor.

Moderator lines to reflectors can only be 2 blocks long since the neutron flux travels to the reflector, then back (a total of 4 blocks)

The moderator line's neutron flux is multiplied by the reflector's reflectivity.

The moderator line's efficiency is also multiplied by the reflector's efficiency factor.

Here is a list of all reflector stats:

Reflector	Reflectivity	Efficiency Factor
Lead-Steel	50%	25%
Beryllium-Carbon	100%	50%
Actual values may vary based on mod configuration

For example, the first moderator line provides 40 neutron flux ((10+10)*2*1) and has an efficiency factor of 55% ((1.1+1.1)/2*0.5)

The second moderator line provides 72 neutron flux ((36+36)*2*0.5) and has an efficiency of 25% ((1+1)/2*0.25)

Irradiators

Irradiators are placed in a reactor to perform recipes using neutron flux.

Irradiators are placed at the end of a moderator line. Each irradiator recipe requires a specific amount of neutrons, so more neutron flux will speed up the recipes. (One moderator is enough for a slow irradiator)

For example, this irradiator will receive 144 neutron flux from the fuel cell. The cell gains no neutron flux from this moderator line.

Each Irradiator recipe has an efficiency multiplier. The moderator line's efficiency is multiplied by the irradiator recipe's efficiency multiplier.

If the irradiator recipe also produces heat, the irradiator will generate heat for each point of neutron flux provided to the irradiator.

Here is a list of all irradiator recipes:

Input	Output	Efficiency	Heat Per Flux
Thorium	Protactinium-Enriched Thorium	0%	0
Protactinium-Enriched Thorium	Protactinium-233	0%	0
Bismuth Dust	Polonium Dust	50%	0
Actual values may vary based on mod configuration

Neutron Shields

Neutron shields can be used to toggle moderator lines and shut down reactors. They can be in placed in place of any moderator, although they do not provide any neutron flux.

Here is a list of all neutron shield stats:

Shield	Efficiency	Heat Per Flux
Boron-Silver	50%	5
Actual values may vary based on mod configuration

Shields generate heat for each point of neutron flux passing through them. Only some of this heat will count towards heating coolant (heat * shield efficiency)

Shields can be closed with a Shield Controller, which will shut down its moderator line, blocking neutron flux between linked cells. If a cell's flux falls below its criticality, it will shut down as well.

For example, This shield will generate 100 heat, from 20 flux passing through it (10 on the way to the reflector, 10 on the way back)

This shield will generate 150 heat, from 30 flux passing through it (20 from the left, 10 from the right)

This shield will generate 180 heat, from 36 flux passing through it. The moderators to its right do not provide it flux, as it is absorbed by the irradiator.

Heat Sinks

Heat Sinks are placed in the reactor to cool it down. Each heat sink has placement rules and a cooling rate. If its rules are met, the heat sink becomes active, and can support other heat sinks.

Here is a list of all heat sinks and their stats:

Heat Sink	Cooling Rate	Requirements
Water Heat Sink	55 H/t	1 Fuel Cell
Iron Heat Sink	50 H/t	1 Moderator
Redstone Heat Sink	85 H/t	1 Fuel Cell and 1 Moderator
Quartz Heat Sink	80 H/t	1 Redstone Heat Sink
Obsidian Heat Sink	70 H/t	Axial Glowstone Heat Sinks
Nether Brick Heat Sink	105 H/t	1 Obsidian Heat Sink
Glowstone Heat Sink	90 H/t	2 Moderators
Lapis Heat Sink	100 H/t	1 Fuel Cell and 1 Casing
Gold Heat Sink	110 H/t	Exactly 2 Iron Heat Sinks
Prismarine Heat Sink	115 H/t	2 Water Heat Sinks
Slime Heat Sink	145 H/t	Exactly 1 Water and 2 Lead Heat Sinks
End Stone Heat Sink	65 H/t	1 Reflector
Purpur Heat Sink	95 H/t	1 Reflector and 1 Iron Heat Sink
Diamond Heat Sink	200 H/t	1 Fuel Cell and 1 Gold Heat Sink
Emerald Heat Sink	195 H/t	1 Moderator and 1 Prismarine Heat Sinks
Copper Heat Sink	75 H/t	1 Water Heat Sink
Tin Heat Sink	120 H/t	Axial Lapis Heat Sinks
Lead Heat Sink	60 H/t	1 Iron Heat Sink
Boron Heat Sink	160 H/t	1 Quartz Heat Sink and 1 Casing
Lithium Heat Sink	130 H/t	Exact-Axial Lead Heat Sinks and 1 Casing
Magnesium Heat Sink	125 H/t	Exactly 1 Moderator and 1 Casing
Manganese Heat Sink	150 H/t	2 Fuel Cell
Aluminum Heat Sink	175 H/t	1 Quartz and 1 Lapis Heat Sinks
Silver Heat Sink	170 H/t	2 Glowstone and 1 Tin Heat Sinks
Fluorite Heat Sink	165 H/t	1 Gold and 1 Prismarine Heat Sinks
Villiaumite Heat Sink	180 H/t	1 Redstone and 1 End Stone Heat Sinks
Carobbiite Heat Sink	140 H/t	1 End Stone and 1 Copper Heat Sinks
Arsenic Heat Sink	135 H/t	Axial Reflectors
Liquid Nitrogen Heat Sink	185 H/t	2 Copper and 1 Purpur Heat Sinks
Liquid Helium Heat Sink	190 H/t	Exactly 2 Redstone Heat Sinks
Enderium Heat Sink	155 H/t	3 Moderators
Cryotheum Heat Sink	205 H/t	3 Fuel Cells
Actual values may vary based on mod configuration

There are a few types of placement rules:

• 2 Fuel Cells requires 2 or more fuel cells directly adjacent to this heat sink
• Exactly 2 Redstone Heat Sinks requires exactly 2 redstone heat sinksdirectly adjacent to this heat sink
• Axial Lapis Heat Sinks requires 2 lapis heat sinks on opposite sides of this heat sink. There can be more than 2 lapis heat sinks, but at least 2 must be on opposite sides
• Exact-Axial Lead Heat Sinks requires exactly 2 lead heat sinks, which must be on opposite sides of this heat sink.

Note that you cannot have casing blocks inside the reactor. Heat Sinks that require casings must be on the outer edges of the reactor.

Clusters

Clusters are groups of cells, irradiators, shields, and heat sinks that are connected together. Every cluster must be connected to the casing. Clusters can be connected to each other and to the casing with Conductors.

If a cluster has a net heat of > 10, all its fuel cells will run through fuel faster than normal. (The cluster will also melt down once its heat buffer fills up)

If a cluster has a net heat of < -10, it will get an extra penalty to efficiency

(The actual thresholds may vary based on mod configuration)

Sparsity Penalty

If the reactor has less than 75% functional blocks, it will get an extra penalty to efficiency. Functional blocks include all valid cells, moderators, reflectors, irradiators, shields, and heat sinks, but not conductors.

(The actual threshold may vary based on mod configuration)